Gap control via overmold teeth and hard stops

ABSTRACT

A forceps includes an end effector assembly having a stop and a plurality of overmold teeth within at least one jaw member. One (or both) of the jaw members is moveable relative to the other between a spaced-apart position and an approximated position for grasping tissue therebetween. One (or both) of the jaw members includes a stop molded within an insulative housing, and an insulator plate with the overmold teeth formed from plastic. The overmold teeth extend through openings within a sealing plate and protrude past the tissue sealing surface of the sealing plate. The stop primarily controls the gap distance between opposing jaw members by bearing most of an applied load and the overmold teeth assist in controlling the gap distance by bearing the remaining applied load.

CROSS REFERENCE TO RELATED APPLICATION

The present application is continuation of U.S. patent application Ser.No. 13/835,004, filed on Mar. 15, 2013, which claims the benefit of andpriority to U.S. Provisional Application Ser. No. 61/672,347, filed onJul. 17, 2012, the entire contents of which are incorporated herein byreference.

BACKGROUND

The present disclosure relates to surgical instruments and, moreparticularly, to a surgical instrument for controlling gap distancebetween jaw members using hard stops and overmold teeth.

TECHNICAL FIELD

Electrosurgical instruments, e.g., electrosurgical forceps, utilize bothmechanical clamping action and electrical energy to effect hemostasis byheating tissue to coagulate and/or cauterize tissue. Certain surgicalprocedures require more than simply cauterizing tissue and rely on theunique combination of clamping pressure, precise electrosurgical energycontrol and gap distance (i.e., distance between opposing jaw memberswhen closed about tissue) to “seal” tissue.

One method of controlling the gap distance, uses one or more ceramicdots on one or both jaw members. The ceramic dots are deposited atop oneor both jaw members. The ceramic dots may be vapor deposited ontosealing plates. The ceramic dots project from the tissue engagingsurface of one or both jaw members and the ceramic dots form acorresponding series of nonconductive stop members for controlling theseparation distance between opposing jaw members when closed abouttissue. Most ceramics are stable at elevated temperatures and usuallyexhibit low thermal and electrical conductivities. In addition, ceramicmaterials have high melting points and are resistant to oxidation,corrosion, or other forms of degradation to which metals are usuallymore prone. However, ceramic dots add substantial cost to themanufacture of the jaw members.

SUMMARY

As used herein, the term “distal” refers to the portion that is beingdescribed which is further from a user, while the term “proximal” refersto the portion that is being described which is closer to a user.

In accordance with one aspect of the present disclosure, a forcepsincludes an end effector assembly having a stop and a plurality ofovermold teeth within at least one jaw member. One (or both) of the jawmembers may be moveable relative to the other between a spaced-apartposition and an approximated position for grasping tissue therebetween.One (or both) of the jaw members includes a stop molded within aninsulative housing, and an insulator plate with the overmold teethformed from plastic. The overmold teeth extend through openings within asealing plate and protrude past the tissue sealing surface of thesealing plate. The stop primarily controls the gap distance betweenopposing jaw members by bearing most of an applied load and the overmoldteeth assist in controlling the gap distance by bearing the remainingapplied load.

According to an aspect of the present disclosure, an end effectorassembly includes a pair of opposing jaw members configured to primarilycontrol a gap distance between opposing jaw members. At least one of thejaw members includes an insulative base including a hard stop. The hardstop is configured to primarily control a gap distance between theopposing jaw members. At least one of the jaw members also includes asupport base coupled to the insulative housing and an insulative platecoupled to the support base and formed with a plurality of overmoldteeth and a sealing plate mounted to the insulative plate. The sealingplate includes a plurality of openings formed therein. The plurality ofovermold teeth extend through the corresponding plurality of openings onthe sealing plate and are configured to assist in controlling the gapdistance between opposing jaw members.

According to aspects of the present disclosure, the hard stop may beremotely disposed relative to the sealing plate.

According to other aspects of the present disclosure, the plurality ofovermold teeth may be configured to contact the corresponding pluralityof overmold teeth on the opposing jaw member. Alternatively, theplurality of overmold teeth may be configured to contact the sealingplate on the opposing jaw member. The plurality of overmold teeth mayalso be located along a blade slot defined in the seal plate tofacilitate grasping of tissue during tissue division.

According to a further aspect of the present disclosure, the hard stopmay be configured to primarily control the gap distance by bearing mostof the applied load as the end effector assembly grasps tissue.

According to another aspect of the present disclosure, the hard stop maybe engaged when jaw members flex under the applied load.

According to yet another aspect of the present disclosure, a method offorming a jaw member of an end effector includes the steps of forming asupport base and forming an insulative plate with a plurality ofovermold teeth. The method further includes the steps of forming asealing plate with a plurality of openings and mounting the insulativebase to the support base. The method further includes the step ofmounting the sealing plate onto the insulative plate with the pluralityof overmold teeth extending through the plurality of openings on thesealing plate. The method further includes the step of overmolding aninsulative housing with a hard stop around the support base to form thejaw member. When the end effector is closed around tissue the hard stopis configured to bear the majority of an applied load and the overmoldteeth bear a smaller remaining portion of the applied load

The method may further include that the insulative plate may be formedby injection molding. The method may also include that the hard stop maybe remotely disposed relative to the sealing plate.

According to another aspect of the present disclosure, an end effectorassembly includes a pair of opposing jaw members. At least one of thejaw members includes an insulative housing including a hard stop formedfrom a plastic material. The hard stop may be configured to bear themajority of an applied load as the end effector assembly is closedaround tissue. At least one of the jaw members further includes asupport base coupled to the insulative housing and an insulative platemolded from the plastic material with a plurality of overmold teeth anda sealing plate mounted to the insulative plate. The sealing plateincludes a plurality of openings formed therein. The plurality ofovermold teeth extend through the corresponding plurality of openings onthe sealing plate past a tissue sealing surface of the sealing plate.The plurality of overmold teeth may be configured to ensure that theopposing jaw members are an appropriate gap distance apart.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described herein withreference to the drawings wherein:

FIG. 1 is a front, perspective view of an endoscopic surgical instrumentconfigured for use in accordance with the present disclosure;

FIG. 2 is a front, perspective view of an open surgical instrumentconfigured for use in accordance with the present disclosure;

FIG. 3 is a front, perspective view of one embodiment of a jaw memberconfigured for use with the surgical instrument of FIG. 1 or 2;

FIG. 4 is a side, perspective view of an end effector assemblyconfigured for use with the surgical instrument of FIG. 1 or 2;

FIG. 5 is cross-sectional view of an end effector assembly configuredfor use with the surgical instrument of FIG. 1 or 2;

FIGS. 6A and 6B are exploded views of the opposing jaw members of FIG.4;

FIGS. 7A-7C are front, perspective views of different embodiments of anend effector assembly configured for use with the surgical instrument ofFIG. 1 or 2; and

FIG. 8 is a flowchart of a method for forming a jaw member according tothe present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described in detail withreference to the drawing figures wherein like reference numeralsidentify similar or identical elements.

Referring now to FIGS. 1 and 2, FIG. 1 depicts a forceps 10 for use inconnection with endoscopic surgical procedures and FIG. 2 depicts anopen forceps 10′ contemplated for use in connection with traditionalopen surgical procedures. For the purposes herein, either an endoscopicinstrument, e.g., forceps 10, or an open instrument, e.g., forceps 10′,may be utilized in accordance with the present disclosure. Obviously,different electrical and mechanical connections and considerations applyto each particular type of instrument; however, the novel aspects withrespect to the end effector assembly and the operating characteristicsthereof remain generally consistent with respect to both the open andendoscopic configurations.

Turning now to FIG. 1, an endoscopic forceps 10 is provided defining alongitudinal axis “X-X” and including a housing 20, a handle assembly30, a rotating assembly 70, a trigger assembly 80, an actuator 90, andan end effector assembly 100. Forceps 10 further includes a shaft 12having a distal end 14 configured to mechanically engage end effectorassembly 100 and a proximal end 16 that mechanically engages housing 20.Housing 20 contains the internal working components of the forceps 10which are not described herein but which may be found in commonly-ownedU.S. Pat. No. 7,156,846, the entire contents of which are herebyincorporated by reference herein.

End effector assembly 100 is shown attached at the distal end 14 ofshaft 12 and includes a pair of opposing jaw members 110 and 120. Jawmembers 110, 120 are moveable between a spaced-apart position and anapproximated position for grasping tissue therebetween. End effectorassembly 100 is designed as a unilateral assembly, e.g., where jawmember 120 is fixed relative to shaft 12 and jaw member 110 is moveableabout pivot 103 relative to shaft 12 and fixed jaw member 120. However,end effector assembly 100 may alternatively be configured as a bilateralassembly, e.g., where both jaw member 110 and jaw member 120 aremoveable about a pivot 103 relative to one another and to shaft 12.

With continued reference to FIG. 1, forceps 10 also includeselectrosurgical cable 610 that connects forceps 10 to a generator (notshown) or other suitable power source, although forceps 10 mayalternatively be configured as a battery powered instrument. Cable 610includes a wire (or wires) (not explicitly shown) extending therethroughthat has sufficient length to extend through shaft 12 in order toprovide electrical energy to at least one of the jaw members 110 and 120of end effector assembly 100. Trigger 82 of trigger assembly 80 may beselectively depressed to advance a knife (not shown) between jaw members110, 120 to cut tissue grasped therebetween. Actuator 90, on the otherhand, is selectively activatable to supply electrosurgical energy to one(or both) of jaw members 110, 120, as will be described in greaterdetail below.

With continued reference to FIG. 1, handle assembly 30 includes fixedhandle 50 and a moveable handle 40. Fixed handle 50 is integrallyassociated with housing 20 and handle 40 is moveable relative to fixedhandle 50. Rotating assembly 70 is rotatable in either direction about alongitudinal axis “X-X” to rotate end effector 100 about longitudinalaxis “X-X.” Moveable handle 40 of handle assembly 30 is ultimatelyconnected to a drive assembly (not shown) that, together, mechanicallycooperate to impart movement of jaw members 110 and 120 between thespaced-apart position and the approximated position to grasp tissuedisposed between jaw members 110, 120. As shown in FIG. 1, moveablehandle 40 is initially spaced-apart from fixed handle 50 and,correspondingly, jaw members 110, 120 are in the spaced-apart position.Moveable handle 40 is depressible from this initial position to adepressed position corresponding to the approximated position of jawmembers 110, 120.

Referring now to FIG. 2, an open forceps 10′ is shown including twoelongated shafts 12 a and 12 b, each having a proximal end 16 a and 16b, and a distal end 14 a and 14 b, respectively. Similar to forceps 10(FIG. 1), forceps 10′ is configured for use with end effector assembly100. More specifically, end effector assembly 100 is attached to distalends 14 a and 14 b of shafts 12 a and 12 b, respectively. As mentionedabove, end effector assembly 100 includes a pair of opposing jaw members110 and 120 that are pivotably connected about a pivot 103. Each shaft12 a and 12 b includes a handle 17 a and 17 b disposed at the proximalend 16 a and 16 b thereof. Each handle 17 a and 17 b defines a fingerhole 18 a and 18 b therethrough for receiving a finger of the user. Ascan be appreciated, finger holes 18 a and 18 b facilitate movement ofthe shafts 12 a and 12 b relative to one another that, in turn, pivotsjaw members 110 and 120 from an open position, wherein the jaw members110 and 120 are disposed in spaced-apart relation relative to oneanother, to a closed position, wherein the jaw members 110 and 120cooperate to grasp tissue therebetween.

A ratchet 30′ may be included for selectively locking the jaw members110 and 120 relative to one another at various positions duringpivoting. Ratchet 30′ may include graduations or other visual markingsthat enable the user to easily and quickly ascertain and control theamount of closure force desired between the jaw members 110 and 120.

With continued reference to FIG. 2, one of the shafts, e.g., shaft 12 b,includes a proximal shaft connector 19 that is configured to connect theforceps 10′ to a source of electrosurgical energy such as anelectrosurgical generator (not shown). Proximal shaft connector 19secures an electrosurgical cable 610′ to forceps 10′ such that the usermay selectively apply electrosurgical energy to jaw member 110 and/orjaw member 120 of end effector assembly 100.

Referring now to FIGS. 3-5, one embodiment of jaw members 210 and 220 isprovided in accordance with the present disclosure. FIG. 3 shows a frontperspective view of jaw member 220. Jaw member 220 includes aninsulative housing 227, support base 230, insulative plate 222, andsealing plate 240. Molded within the insulative housing 227 is a hardstop 225 configured to limit the gap distance when jaw members 220 and210 (see FIG. 4) are closed around tissue. Additionally, overmold teeth235 a-235 e assist in limiting the gap distance “G” (See FIG. 4) whenjaw members 210 and 220 are closed around tissue.

One or more overmold teeth 235 a-235 e on jaw member 220 contact one ormore respective opposing overmold teeth 285 a-285 e (see FIG. 4) on jawmember 210 as the jaw members 210, 220 are closed due to a tip-bias.Then as the jaw members 210, 220 flex one or more hard stops 225, and/or275 are engaged. When the hard stops 225 and/or 275 are engaged, hardstops 225 and/or 275 bear most of the load. By having the one or moreovermold teeth 235 a-235 e, 285 a-285 e contact first ensures that thejaw members are at the appropriate gap distance “G” (see FIG. 4). Inother words, the tip-bias ensures that the jaw members 210, 220 areproperly closing.

Alternatively, hard stop 225 and/or 275 may be configured to control theinitial gap distance between jaw members 210 and 220 and to bear most ofthe load as the tissue is compressed between jaw members 210 and 220while overmold teeth 235 a-235 e control the gap distance while jawmembers 210 and 220 flex as they seal tissue.

As the jaw members 210, 220 clamp together around tissue, hard stop 225and/or hard stop 275 (See FIG. 6A) and overmold teeth 235 a-235 e and/or285 a-285 e maintain the gap distance “G” with the hard stop 225 and/or275 bearing most of the applied load. The gap distance is about 0.001inches to about 0.005 inches.

Hard stop 225 may be disposed at a remote location or away from the hightemperatures of seal plate 240 (e.g., closer to proximal end 221 of jawmember 220) to reduce deflection of hard stop 225 under loading. By hardstops 225 and/or 275 being removed from the high temperatures of theseal plates 240, 312, the hard stops 225 and/or 275 can bear a majorityof the applied load when a user grasps tissue with end effector 200without the unnecessary risk of melting or deflection.

The overmold teeth 235 a-235 e and/or 285 a-285 e may be used to assistthe user in gripping tissue during grasping. The overmold teeth 235a-235 e and/or 285 a-285 e are relatively small in size to reduce theeffect of the overmold teeth 235 a-235 e and/or 285 a-285 e on tissuesealing performance. For example the overmold teeth may range from about0.020 inches to about 0.050 inches in diameter. However, the size of theteeth can vary based on the size of the jaw members. Initially, one ormore overmold teeth 235 a-235 e and/or 285 a-285 e may be used to checkthat jaw members 210, 220 are closing to the gap distance “G”. Then, asthe jaw members 210, 220 flex then hard stops 225 and/or 275 makecontact and bear most of the load. Alternatively, the overmold teeth 235a-235 e and/or 285 a-285 e may be used to secondarily control the gapdistance “G” as the jaw members 220, 210 flex. For example, when the jawmembers flex 220, 210 under a particular loading condition, only oneovermold tooth 235 a may make contact with a corresponding opposingovermold tooth 285 a. Alternatively, when the jaw members 220, 210 areunder a different loading condition, more overmold teeth 235 a-235 e onjaw member 220 may make contact with corresponding overmold teeth 285a-285 e on jaw member 210, however not all overmold teeth 235 a-235 eand/or 285 a-285 e need to contact each other to maintain proper gapdistance “G”.

Turning to FIGS. 6A and 6B, the opposing jaw members 210 and 220 includesupport bases 319 and 230 that extend distally from flanges 313 and 221,respectively. The support bases 319 and 230 are configured to supportinsulative plates 322 and 222, which, in turn, support electricallyconductive sealing plates 312 and 240 thereon. Sealing plates 312 and240 may be affixed atop the insulative plates 322 and 222, respectively,and support bases 319 and 230, respectively, in any suitable mannerincluding snap-fit, over-molding, stamping, ultrasonically welded, etc.The support bases 319 and 230, insulative plates 322 and 222, andsealing plates 312 and 240 are encapsulated by the outer insulativehousings 316 and 227 by way of a subsequent overmolding process. The jawmembers 210 and 220 are connected via an ultrasonic weld or othersuitable joining process to electrical jaw leads 325 a and 325 b,respectively.

The jaw members 210 and 220 also include proximal flanges 313 and 221extending proximally from the support bases 319 and 230, respectively,each of which includes an elongated angled cam slot 317 and 327,respectively, defined therethrough. The electrically conductive sealingplates 312 and 240 and the insulator plates 322 and 222 includerespective longitudinally-oriented knife slots 315 a, 315 a′ and 315 b,315 b′, respectively, defined therethrough for reciprocation of theknife blade (not shown). Jaw member 220 further includes one or moreovermold teeth 235 a-235 e disposed on the inner facing surface ofinsulative plate 222 to define a gap between opposing jaw members 210and 220 during sealing and/or cutting of tissue. The overmold teeth 235a-235 e are molded within insulative plate 222 when the insulative plate222 is molded. Types of plastic material that may be used are Amodel®,Trogamid®, PEKK, G-PEAK, PEEK, Thermotuff™, Ultem®, etc., all of whichmay be mineral and/or fiber reinforced.

The overmold teeth 235 a-235 e may be located along blade slot 315 b′.The overmold teeth 235 a-235 e extend through openings 237 a-237 ewithin seal plate 240 and are slightly higher in elevation than sealplate 240 to prevent seal plates 312 and 240 from touching and creatinga short between the seal plates 312, 240. Additionally, when theovermold teeth 235 a-235 e are located along blade slot 315 b′, theovermold teeth 235 a-235 e help grip tissue closer to where the divisiontakes place and may produce a more reliable cut even when a blade (notshown) is not as sharp. Additionally, if insulator plate 322 includesone or more overmold teeth 285 a-285 e, then overmold teeth 285 a-285 eextend through openings 287 a-287 e within seal plate 312 and areslightly higher in elevation than seal plate 312 to prevent seal plates312 and 240 from touching. Overmold teeth 285 a-285 e are formed in thesame manner used to create overmold teeth 235 a-235 e. Additionally, ifovermold teeth 285 a-285 e are spaced apart along blade slot 315 a′,then overmold teeth 285 a-285 e assist in gripping tissue closer towhere the division takes place.

Referring to FIGS. 7A-7C, the overmold teeth 235 a-235 e and/or 285a-285 e may be located in any location along insulative plates 222, 322and either insulative plate 222 or 322 may include one or more overmoldteeth 235 a-235 e and/or 285 a-285 e. FIG. 7A shows one embodiment of anend effector assembly 700 where the overmold teeth 235 a-235 e on jawmember 220 contact the mating row of overmold teeth 285 a-285 e on jawmember 210. With end effector 700, the overmold teeth 235 a-235 e and/or285 a-285 e are almost always contacting plastic. FIG. 7B shows analternative embodiment with end effector assembly 710, with overmoldteeth 265 a-265 g on alternating sides blade slot 315 b (See FIG. 6B).With end effector 710, each tooth of the overmold teeth 265 a-265 g maycontact directly against seal plate 312 because of the symmetry withovermold teeth (not shown) on jaw member 210. However, if overmold teeth265 a-265 g are of opposite symmetry to overmold teeth (not shown) onjaw member 210, then each tooth may contact an opposite overmold tooth,i.e. contact plastic and not a sealing plate 240, 312. Additionally, ifonly one jaw member 210 or 220 has overmold teeth 235 a-235 e or 285a-285 e, then one or more teeth of the overmold teeth 235 a-235 e or 285a-285 e contact the opposite seal plate 240, 312.

FIG. 7C shows an alternative end effector assembly 720. End effectorassembly 720 includes a row of overmold teeth 295 a-295 g along a firstside 725 of blade slot 315 b on jaw member 220 and a row of overmoldteeth 297 a-297 g along a second side 727 of blade slot 315 a on jawmember 210. When end effector assembly 720 is closed around tissue,overmold teeth 295 a-295 g and 297 a-297 g contact directly against sealplate 312, 240 on respective opposing jaw members 210, 220.Alternatively, end effector 720 may be configured with a row of overmoldteeth 295 a-295 g along a first side 725 of blade slot 315 b on jawmember 220 and a row of overmold teeth 297 a-297 g along a first side726 of blade slot 315 a on jaw member 210. In this alternativeembodiment, the overmold teeth 295 a-295 g and 297 a-297 g directlyoppose each other and are almost always contacting plastic.

FIG. 8 is a flow diagram of process 800 for forming a jaw member 210,220. The process 800 starts at step 805, and at step 810 the supportbase 230, 319 is formed. The support base 230, 319 may be formed of aplastic material by an injection molding process. Next, at step 820, aninsulative plate 222, 322 with a plurality of overmold teeth 235 a-235e, 285 a-285 e is formed of a plastic material by an injection moldingprocess. Then at step 830, the sealing plate 240, 312 is formed from aconductive material with a plurality of openings 237 a-237 e, 287 a-287e. Next at step 840, the insulative plate 222, 312 is mounted to thesupport base 230, 319. Then at step 850, the sealing plate 240, 312 ismounted to the insulative plate 222, 312 with the plurality overmoldteeth 235 a-235 e, 285 a-285 e extending through the plurality ofopenings 237 a-237 e, 287 a-287 e, respectively. The sealing plate 240,312 may be affixed atop the insulative plate 222, 312 in any knownmanner in the art, snap-fit, overmolding, stamping, ultrasonicallywelded, etc. The process 800 ends at step 865 after the insulativehousing 227, 316 is formed around support base 230, 319 at step 860.When the insulative housing 227, 316 is formed hard stop 225, 275 isalso formed of a plastic material. One method for forming the insulativehousing 227, 316 is by an overmolding process.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. While several embodiments of the disclosure have been shownin the drawings, it is not intended that the disclosure be limitedthereto, as it is intended that the disclosure be as broad in scope asthe art will allow and that the specification be read likewise.Therefore, the above description should not be construed as limiting,but merely as exemplifications of particular embodiments. Those skilledin the art will envision other modifications within the scope and spiritof the claims appended hereto.

What is claimed is:
 1. An end effector assembly comprising: a pair ofopposing jaw members, at least one of the jaw members including: aninsulative plate formed with a plurality of overmold teeth; and asealing plate mounted to the insulative plate, the sealing plateincluding a plurality of openings defined therein, the plurality ofovermold teeth extending through the corresponding plurality of openingsdefined in the sealing plate and configured to control a gap distancebetween the opposing jaw members.
 2. The end effector assembly accordingto claim 1, wherein the sealing plate includes a tissue contactingsurface, the plurality of overmold teeth extending from the tissuecontacting surface and through the plurality of openings.
 3. The endeffector assembly according to claim 1, wherein the plurality ofovermold teeth contact a corresponding plurality of overmold teeth onthe opposing jaw member.
 4. The end effector assembly according to claim1, wherein the plurality of overmold teeth contact the sealing plate onthe opposing jaw member.
 5. The end effector assembly according to claim1, wherein the plurality of overmold teeth are located along a bladeslot defined in the seal plate to facilitate grasping of tissue duringtissue division.
 6. A method of forming a jaw member of an end effector,comprising; forming an insulative plate with a plurality of overmoldteeth; forming a sealing plate having a plurality of openings definedtherein; and mounting the sealing plate onto the insulative plate withthe plurality of overmold teeth extending through the plurality ofopenings in the sealing plate, wherein when the end effector is closedaround tissue, the overmold teeth are configured to bear a portion of anapplied load between the jaw member and an opposing jaw member.
 7. Themethod according to claim 6, wherein insulative plate is formed byinjection molding.
 8. A jaw member for an end effector assembly, the jawmember comprising: an insulative plate molded from a plastic materialwith a plurality of overmold teeth; and a sealing plate mounted to theinsulative plate, the sealing plate including a plurality of openingsdefined therein, the plurality of overmold teeth extending through thecorresponding plurality of openings defined in the sealing plate andconfigured to ensure an appropriate gap distance between an opposing jawmember.
 9. The jaw member according to claim 8, wherein the sealingplate includes a tissue contacting surface, the plurality of overmoldteeth extending from the tissue contacting surface and through theplurality of openings.
 10. The jaw member according to claim 8, whereinthe plurality of overmold teeth are located along a blade slot definedin the seal plate.